Adding a Real Clock Calendar to Your Raspberry PI

Introduction: Adding a Real Clock Calendar to Your Raspberry PI

The Raspberry Pi doesn’t have a little coin-battery-powered ‘Real Time Clock’ (RTC) module, which keeps time even when the power is off, or the battery removed.

To keep costs low and the size small, an RTC is not included with the Raspberry Pi. If your Raspberry Pi is connected to the Internet via Ethernet or WiFi, the time/date will be automatically updated from the global ntp (nework time protocol) servers.

For stand-alone projects with no network connection, you will not be able to keep the time when the power goes out.

In this project we will show you how to add a RTC Click shield from Mikroelektronika, without the use of iron solder or breadboard.

This is possible using a Click Shield ( MIKROE 1512 ) for Raspberry PI from Mikroelektronika, easily found on RS Components (http://uk.rs-online.com/web) RS SN 811-7024 and one RTC Click shield RS SN 820-9832.

We just need to insert the two Click board, please have a look to the images.

Step 2: Install the I2c-tools Utility

The I2C bus allows multiple devices to be connected to your Raspberry Pi, each with a unique address, that can often be set by changing jumper settings on the module. It is very useful to be able to see which devices are connected to your Pi as a way of making sure everything is working.

To do this, it is worth running the following commands in the Terminal to install the i2c-tools utility:

sudo apt-get install python-smbus

sudo apt-get install i2c-tool

Depending on your distribution, you may also have a file called /etc/modprobe.d/raspi-blacklist.conf.

If you do not have this file then there is nothing to do, however, if you do have this file, you need to edit it and comment out the lines below:

blacklist spi-bcm2708

blacklist i2c-bcm2708

.. by putting a # in front of them. Open an editor on the file by typing

sudo nano /etc/modprobe.d/raspi-blacklist.conf

.. then edit the file so that it appears as above and then save and exit the file using CTRL-x and Y.

which will read the time from the PCF8583 module. If this is the first time the module has been used, it will report back Jan 1 2000, and you’ll need to set the time. Can also happen that it will report an invalid data.